1. Field of the Invention
The present invention relates to reinforced cloth-like composite laminates of cellulosic fibers.
Airlaid technology is used to form a variety of cellulosic paper products. It is usually desirable that cellulosic composite laminates exhibit a number of qualities such as a cloth-like appearance, excellent wet and dry strength, exceptional porosity, very good abrasion resistance and wash durability, bulk and water holding capacity, and a lack of a paper rattle. Cellulosic composite laminates that possess these qualities can be used to make towels or tissues that are valuable assets in the performance of a variety of tasks. For example, such a towel or tissue can be used by doctors or nurses as a highly effective and strong hand towel or tissue in both a hospital and an office.
Moreover, it is desirable that the wet and dry strength, elongation and breaking strength of the resulting composite laminate be stronger than the sum of the individual layers making up the composite laminate. Such a composite laminate would be very durable and effective in a number of applications.
2. Description of the Background Art
In previous processes and cellulosic composite laminates whereby cellulosic fiber webs are reinforced with a reinforcing nonwoven material or scrim, difficulties have been encountered in achieving an effective bonding between the cellulosic fiber webs and the reinforcing nonwoven material. Such difficulties reduce the overall strength of the composite structure and lead to puckering of the finished fabric. In some cases excessive amounts of latex have been utilized in an attempt to strengthen the bonding between the cellulosic fiber webs and the reinforcing material which, of course, adversely affects the overall cost of manufacture. In this regard, reference is made to U.S. Pat. No. 4,636,418, to Kennard et al, and U.S. Pat. Nos. 4,634,621, 4,637,949, and 4,731,276, all to Manning et al. Each of these references discloses the combination of a reinforcing nonwoven material or scrim provided with cellulosic fiber webs on one or both sides thereof and the bonding thereof with a latex adhesive. In Kennard et al, the latex is used as the only means for joining the layers together, and it is specifically disclosed that the nonwoven material can be bonded and wet formed prior to lamination. In the Manning et al patents, particularly the '621 patent, the reinforcing layer is a scrim that is coated with a thermoplastic binder onto which the cellulosic fiber layers are provided, wherein the scrim and two cellulosic layers are passed through a station to heat the laminate to a temperature sufficient to activate the thermoplastic binder. None of these references, however, disclose the use of a wetlaid bicomponent fiber web as the nonwoven reinforcing web. Moreover, no component portion of the nonwoven fibers of the reinforcing web or scrim are used themselves in order to bond the cellulosic fiber webs to the nonwoven web or scrim.